Manufacture of soap



j Patented Feb. 13, 1945 UNTITEDSTATES PATENT ICE i 2,369,372 Q 1 tMANUrscTUnn F SOAP:

No Drawing.

Leopold Sender; Baltimore, Md., assignortoflhe Sharples Corporation, P aporation of Delaware y H Application Decemberii, 1941, I ,1, SerialNo.422,231 I t t hiladelphia, Pa. a corfepoiai is, (minc -pleas) Thepresent invention pertains to the-menu lem of obtaining an improvedyield of soap or,

material: which can be saponified by further treatment. More,specifically; a process is pro- I terials in the subsequent soap makingoperation,

mass from-which the subsequent soaphis'made,

and these impurities must, of course, be removed vided by which soapnigres' may be subjected to purification for removal of materialincluding dirt and other undesired impurities togetherwith a small partof thesoap content of the nigre, 9

from the remainder of the nigre, "and the soap or soap-forming acidcontent ofthe material, i removedfrom the nigrethereafter recovered fromthe impurities. i i

Processes for removing impuritie from soap nigres have beenproposedheretofore, andI do not'claim anyiparticular process foreffecting such removal as a part of the present invention. One method ofefiecting. such purification consists in simple centrifugation,preferably by a centrifugal containing peripheral discharge outletscontrolled by valves through which theimpurities are-intermittentlydischarged. In the practice,

wi lson serial No. 389,888, filed April 23, 11941, for Manufactureofssoap. In accordance iwith this method, the nigre is first treatedwith a source Another method of purifying,

from this I subsequently made soap in the fitting step performed on ,thesaponified mass, if this sistently withproduction'of a soap ofsatisfactory quality, but a point is inevitably reached in recyclingsuccessivebatches of nigre at which the nigre contains such a largeproportion of impurities that it canznolonger be recycled consistentlwith manufacture ofsatisfactory soap. a N

--oByypurifyin'gthe' nigre by one of the types of operation discussedabove before reoyclinglto a subsequent. soap making operation, asubstantial proportion of the impurities of the Snigreis re- .moved,with the result that operations of re-:

cycling the i nigre may be continuediin a longer series ofoperationsithan could be done if such purification werenotwaccomplished. 1 The purification of the nigre thus effects animportant economy byimaking it possible to repeat therecyclin operationthrough a longersequence of ofacid, which may-be an organic or inorganicacid or ester (e. g., asoap-forming ester), in order I t to reduce thefree alkali content of the nigre and convert it to a condition in whichtheiimpurities may bemore effectively removed upon subsequentcentrifugation; The process covered 35, fication step. In case ofseparation of the im inthis application constitutesthe best method knownto me for efiecting removal of impurities,

and constitutes the preferred operation by which impurities areiremovedfrom the nigre inmthe practice of the present inventionu i In theconventional manufacture of soap, it is customary to utilizethesoapvalues contained in'thenigre by mixing'the nigre withifat andautilizing the soap contained inthe nigre in this manner, there arece'rtain "economic limitations.

In introducing the nigre along with other: ma-

operations than could otherwise be feasibly accomplished. 5 1

While purification of the nigre before recycling .is advantageous forthe reasons discussed above, suchipurification is attended by the,draw-hack that a certainamount of soap is inevitably lost inconnectionwithithe performance of the puri purities centrifugally, for example,the impurities obtained-fbythe centrifugal operation must of necessitycontain acertain amount of soap. In i any separating operation, best:results as to puri ficationof one of the :products of the separation canbe: attained by permitting the other product gether with the impurities,apart of the soap values or the mere. Any attempt to separate these;impurities without removing. a part of the soapivalues of the 'nigrealongwith the impurities resultstin impairment ofefficiency ofseparation of'the impurities, withtheresultthat realization of thebenefit of efficient removal of the impurities is not attained, and thatthe number of feasible repetitions of the step of recycling the nigre iscorrespondingly limited, a result which constitutes partial defeat ofthe main object of the purification. The operator is thus confrontedwith the dilemma that, if he effects the best pos-' sible purificationof the nigre, substantialquantitles of soap valuesare lost, but that, ifhe attempts to minimize loss of the soap values in thenigre, thepurification operation is relatively inefficient, with the result thatattainment of the principal object of the purification step becomesimpracticable. The attainment of'the objects of maximum eificiency ofpurification with minimum loss of soap values with the impurities thusapparently constitutes an attempt to reconcile essentiallyirreconcilable factors.

A feature of the present invention consists in the fact that it includesa sequence of steps in removal of impurities from the nigr'e andrecovcry of soap values by which maximum efiiciency is attained in thepurification step, with attendant'removal of a substantial part of thesoap from the nigre in this step, and the soap values are subsequently.recovered from the fraction containing the impurities for reuse in thesoap making process, or for other appropriate use to which-these soapvalues or acids derived there with maximum efliciency of purification ofthe nigre, and'in order to accomplish this object,

the impurities removed from thenigre contain a substantial proportion ofsoap. By performing the first step of the process in this manner, themain body of the nigre is purified to a degree which will permit it tobe mixed with fur ther quantities of soap-forming materials in themanufacture ofa further quantity of soap with a minimum of contaminationof the. further quantity of soap by impurities retained. in the nigrefrom the previous soap making operation.-

The performance of the purification step in the manner discussed aboveobviously entails substantial loss of soap values from the nigretreated. In the practice of the present invention, this loss iscompensated by recovery of these values from the impurities with whichthey. are removed from the main body of the nigre in the initialpurification step. Thus, in case of separation of dirt from soap nigrein a centrifugalseparator of the valve bowl type, impurities aredischarged peripherally through the valve-controlled outlets togetherwith a part of the soap of the nigreywith the result that the nigre issatisfactorily purified for reuse, and the peripherally dischargedfraction is then subjected to the subsequent steps of the process forrecovery of soap contained therein. The removal of the soap .values fromthe impurities with which they are separated from the main body of thenigre may be accomplished by dilution of these impurities with water todilute the soap, and subsequent separation of the impurities from theresultant soap solution. The diluted soap solution so ob- CEK tained maybe used in the manufacture of 'a further quantity of soap, or in anyother manner by which the soap values which it contains may be utilized.

Another method of effecting separation of the soap values from theimpurities consists in adding water to the impurities containing thesoap values and thereafter saltingthe soap out of solution in the waterby addition of a salt or alkali. This operation liberates the dirt,which is next removed from the mixture of soap and Water by appropriatemeans, such as centrifugation.

As a still further alternative in the practice of the invention, theimpurities removed from the nigre and containing the soap may be mixedwith a mineral acid capable of springing the soap to form fatty acids.This springing operation will liberate the impurities, with the resultthat these impurities may be separated from the other constituents ofthe mixture by appropriate means, such as centrifugation, for example,by treating the resulting mixture in a centrifugal separator of theso-called clarifier type in order to separate the impurities from themixture of sprung acids and aqueous acid liquor, and then separating thesprung fatty acids and aqueous acid liquor by centrifugation or gravity.Alternatively, the separation may be accomplished in a centrifugal ofthe so-called separator type in which the impurities may be separatedperipherally from the centrifugal at the same time that the sprung acidsare separated from theaqueous acid liquor. 1 1

From the above discussion, it will beseen that a separation of the soapvalues from the impurities may be attained by treatment with water,salts,

alkalies or acids to; liberate the impurities and permit them to beseparated from the soap by. appropriate means, such as centrifugation.As a matter of fact, such separation is facilitated by the addition tothe impurities of any liquid dil- 'uent, and a feature of the inventionconsists in the addition of a liquid diluent, followed bycentrifugation. While the invention has been discussed above' inconnection withan operation involving separation of impurities alongwith soap values from the nigre after the nigre has been separated fromthe main portion of the initially saponified mass, it is possible tocombine the steps of separation of the nigre from thebulk of thesaponified mass and the separation ofimpurities, together with part ofthe soap values; from the nigre. Thus, by employing a centrifugal sepa-'rator of the valve bowl type in separation of neat soap from nigre, thisseparation may be accomplished at the same time that impuritiescontaining soap values are discharged centrifugally from the nigre,which forms an outer stratum in the centrifugal rotor. The presentinvention therefore includes separation of impurities together with soapValues from the nigre, followed by separation of soap values containedin impuri- .ties from those impurities, regardless of whether lowingclaims.

Iclaim: x '1 1. In the treatment of soap nigres, the process comprisingseparating impurities from a soap nigre together with a portionof thesoap of the nigre, thereafter diluting the material separated from thenigre to liberate impurities from the resulting diluted mixture andseparating the impurities from said mixture. t

2. In the treatment of soap nigres, the process comprising separatingimpurities from a soap nigre together with a portion of the soap of thenigre, thereafter diluting the material separated from the nigre toliberate impurities from the resulting dilutedmixture and separating theimpurities from said mixture by centrifugation.

3. In the treatment of soap nigres, the process comprising separatingimpurities from a soap nigre together with a portion of the soap of thenigre, thereafter diluting with water the material separated from thenigre to liberate impurities from the resulting diluted mixture andseparating the impurities from said mixture.

4. In the treatment of soap nigres, the process comprising separatingimpurities from a soap nigre together with a portion of the, soap of themere, thereafter diluting with waterand an electrolyte the materialseparated from the nigre to ture.

5. In the treatment of soap nigres, the process comprising separatingimpurities from a soap nigre together with a portion of the soap of thenigre, thereafter diluting with water and a salt the material separatedfrom the nigre to liberate impurities from the resulting diluted mixtureand separating the impurities from said mixture.

6. In the treatment of soap nigres, the process liberate impurities fromthe resulting diluted mix- I ture and separating the impurities fromsaid mixfrom the resulting diluted mixture and separating the impuritiesfrom said mixture by centrifuga tion.

8. In the treatment of soap nigres, the comprising separating impuritiesfrom a soap nigre together with a portion of the soap or the nigre,.thereafter diluting the material separated from the nigre with a mineralacid to spring the soap separated with the impurities and liberateimpurities from the resulting mixture, and epas rating ,the impuritiesfrom said mixture.

9. In the treatment of soap nigres, the process comprising separatingimpurities from a soap nigre together with a portion of the soap of thenigre, thereafter diluting the material separated from the nigre with amineral acid to spring the soap separated with the impurities andliberate impurities from the resulting mixture, and separating theimpurities from said mixture by centrifugation.

LEOPOLD SENDER.

process

